The present invention relates to a technique suitable or effective for fixedly mounting an annular element to an opening of a component body and, more particularly, to a technique suitable for such mounting when the annular element is used as a stopper or a spring retainer in a valve component. Thus, the invention has remarkable advantages in utilization as, for example, a hydraulic pressure control valve which is used in a brake system of an automotive vehicle or the like.
Generally, there are many structures in which, in mechanical components, an annular member or element is fixedly mounted to an opening of a component body, or another component to be incorporated in the component body which has an end which is fixedly mounted to an inner periphery of the opening. The annular element at the opening serves as a spring retainer, a stopper or the like for preventing the component to be inserted in the component body from coming out of the latter, for example.
Conventionally, and as a well known technique in which an annular element or another internal component is fixedly mounted to the opening of the component body, an annular groove is formed in the inner periphery of the opening, and the annular element such as a C-shaped ring or the like or an end of the internal component is fitted in the annular groove. For instance, EP Patent Publication No. 0 157 158 A2 or GB Patent Application No. 2 195 408A discloses a hydraulic pressure control valve in which an annular groove is formed in an inner periphery of an opening in a valve body. The valve body is adapted to be threadedly engaged with a portion of a brake master cylinder, and faces toward a hydraulic chamber of the brake master cylinder, and an end of a valve spring is fitted in the groove and is supported at the opening.
With the conventional technique described above, first, considerable time is taken since the annular groove must be processed at the inner periphery of the opening and, moreover, an annular element or another internal component must be fitted in the groove. Secondly, because the annular element or another internal component is fitted merely in the groove, the support of the annular element or another component is unsteady.
For instance, the hydraulic pressure control valve disclosed in the aforesaid EP Patent Publication No. 0 157 158 A2 or GB Patent Application No. 2 195 408A will be considered with reference to the unsteadiness of the support of the annular element. Generally, the hydraulic pressure control valve is arranged at a portion of a tandem master cylinder, which communicates with a wheel cylinder for rear wheels. When a failure occurs in a brake circuit for front wheels, a control function of the control valve is released. In case of a failure, a follower piston of the tandem master cylinder moves excessively or violently to incline a poppet valve element of the hydraulic pressure control valve, thereby releasing the pressure regulating function. Accordingly, since biased or one-sided force is applied to a valve spring which urges the poppet valve element, it is important to ensure the support of the valve spring. In this respect, it is impossible for the conventional technique to sufficiently respond to insure the stability or steadiness of the support of the valve spring.